Background: Due to the increase in morbidity and mortality rate, cancer has become an alarming threat tothe human population worldwide. Since cancer is a progressive disorder, timely diagnosis would be helpful toprevent/stop cancer from progressing to severe stage. In Khyber Pakhtunkhwa, Pakistan, most of the time, tumorsare diagnosed with endoscopy and biopsy; therefore rare studies exist regarding the diagnosis of gastrointestinal(GIT) carcinomas based on tumor markers, especially CEA. Objectives: This study made a comparative analysisof CEA in admitted hospitalized stomach and colon cancer patients diagnosed as GIT with biopsy. Materials andMethods: In this study, a total of 66 cases were included. The level of CEA was determined in the blood of thesepatients using ELISA technique. Results: Out of 66 patients, the level of CEA was high in 59.1% of the total,60.7% in colon cancer patients and 57.9 % in stomach cancer patients. Moreover, the incidence of colorectaland stomach cancer was greater in males as compared to females. Patients were more of the age group of 40-60 and the level of CEA was comparatively higher in patients (51.5%) with histology which was moderatelydifferentiated, than patients with well differentiated and poorly differentiated tumor histology. Conclusions:CEA level was high in more than 50% of the total patients. Moreover, CEA exhibited higher sensitivity for colonthan stomach cancer.